Definition

ChEBI: A diisocyanate consisting of diphenylmethane with two isocyanate groups at the 4- and 4'-positions.

Allgemeine Beschreibung

Diphenylmethane-4,4-diisocyanate is a light yellow colored solid. 4,4'-Diphenylmethane diisocyanate is not soluble in water. 4,4'-Diphenylmethane diisocyanate may be toxic by ingestion, inhalation, or skin absorption. If in a solution 4,4'-Diphenylmethane diisocyanate may or may not burn depending on the nature of the material and/or the solvent. It's used to make plastics.

Air & Water Reaktionen

4,4'-Diphenylmethane diisocyanate is not soluble in water.

Reaktivität anzeigen

Isocyanates and thioisocyanates, such as 4,4'-Diphenylmethane diisocyanate, are incompatible with many classes of compounds, reacting exothermically to release toxic gases. Reactions with amines, aldehydes, alcohols, alkali metals, ketones, mercaptans, strong oxidizers, hydrides, phenols, and peroxides can cause vigorous releases of heat. Acids and bases initiate polymerization reactions in these materials. Some isocyanates react with water to form amines and liberate carbon dioxide. Base-catalysed reactions of isocyanates with alcohols should be carried out in inert solvents. Such reactions in the absence of solvents often occur with explosive violence, [Wischmeyer(1969)].

Health Hazard

Breathlessness, chest discomfort, and reduced pulmonary function.

Health Hazard

MDI can present a moderate to severe healthhazard, because of respiration of its vapors and particulates. It can contaminate the environment during foam application; concentrations in air were measured as high as5 mg/m3, mostly as particulates (ACGIH1986).The toxic route is primarily inhalation.The vapor pressure of this compound atambient temperature is very low, 0.00014torr at 25°C. However, when heated to about75°C, the acute health hazard is greatlyenhanced (Hadengue and Philbert 1983). Theacute toxic symptoms were found to besimilar to those of toluene-2,4-diisocyanateand other aromatic isocyanates. Inhalation ofits vapors or particulates can cause bronchitis, coughing, fever, and an asthma-likesyndrome. Other symptoms were nausea,shortness of breath, chest pain, insomnia,and irritation of the eyes, nose, and throat.The immunologic response, however, variedamong humans. Exposure to 0.1–0.2 ppmfor 30 minutes is likely to manifest the acutetoxic effects in humans.MDI is an eye and skin irritant. Contactwith skin can produce eczema. The acuteoral toxicity of this compound is very low,considerably lower than that of toluene-2,4-diisocyanate. The lethal dose for rats was31.7 g/kg. MDI showed positive in mutagenic testingon Salmonella typhimurium. There is noreport that indicates its carcinogenicity.